This invention relates to electrically heating a body of molten material such as glass by means of induction. The invention is applicable to the melting of a material which is susceptible to having electric currents induced therein, and it is particularly applicable to the melting of glass or the like.
It is well known that material may be heated by induced currents when the material is placed within a coil carrying alternating current. An advantage of this type of heating is that the material being heated does not come into contact with the electrical source; e.g., electrodes need not be immersed in the melt. The general concept of inductively heating glass has been disclosed in many patents, for example U.S. Pat. Nos. 1,830,481; 1,906,594; 3,205,292; and 3,244,495. Much of the prior art is limited to small scale embodiments, and large-scale melting of glass by induction heating has not found significant commercial acceptance. The economics of induction heating, however, have not favored its use in the large scale melting of glass and the like. Thermal energy from combustion of fuel has generally been more economical than electric energy for glass melting. Moreover, induction heating has sometimes been considered to entail low efficiency in transferring electrical power into thermal energy. Also, it has been the belief of some in the art that large scale induction heating of glass would entail a prohibitively large induction coil.